Police in Drexel Hill say the 76-year-old guard had just left her post when it happened Tuesday afternoon. Upper Darby police say the guard felt something in her back and that the girl threatened to shoot her if she didn’t get out of the way.

A man who lives nearby intervened and the woman called 911.

Officers say the girl struggled with them as they tried to arrest her. Police believe the object pushed into the woman’s back was a pen.

At the police station, officers say the girl was placed in a containment room and spit on those who came near her. She faces charges of aggravated assault and other counts.